1. Field of the Invention
The present invention is related to an exposure apparatus for an optical disc. More particular, the present invention is related to an exposure apparatus having vibration means capable of vibrating to eliminate vibrations along the propagating direction as a rotation mechanism rotates, thereby pitches between two adjacent tracks on the optical disc can be exposed with a high precision. In addition, the present invention is related to an the exposure apparatus that a three-dimensional shape measuring device can be used for its propagation device.
2. Description of the Prior Art
Nowadays, information or data can be reproduced optically, and an optical disc is well developed for reproducing data from or recording data into the optical disc in an optical manner. The optical disc, for example, can be a compact disc (CD), a compact disc-read only memory (CD-ROM), a compact disc recordable (CD-R), or compact disc rewritable (CD-RW), etc.
In general, an exposure to the optical disc can be done by an exposure apparatus disclosed by Japanese Laid Open 10-293928, for example. The exposure apparatus includes a head fixed on the exposure apparatus through a tiny sliding device for emitting optical beams, and a sliding stage on which a turntable for supporting the optical disc is mounted. The sliding stage can be moved along a radial direction of the turntable by the sliding device installed on the exposure apparatus. The movement of the sliding stage is conducted by the tiny sliding device to compensate the position of the optical head, by which a pitch between adjacent tracks can be exposed with a highly accuracy.
Also, conventionally, in order to achieve that the track pitches with a high precision are formed on the optical disc, a laser interferometer or a laser holo-scale having a high resolution is installed on a slider propagating device that is used for mounting the recording head in a mastering device. By which, a slider propagating deviation of the mastering device is detected, and the propagating deviation is optically corrected by deviating the laser beams using an audio optical deviation device. In addition, the propagating slider and the recording head are integrated by a piezo-actuator. Using the retractable piezo-actuator to let the recording head operate, the tiny propagating deviation of the propagating slider is corrected. (see Japanese Laid Open 10-261245).
Moreover, using the exposure system assembled on the slider, laser beams for exposure are focused by an objective lens. A piezoelectric element of the objective lens for fine-tuning positions of a first tremor table is installed on a second tremor table. The optical disc and the turntable for rotating the optical disc are placed on a position opposite to the objective lens. Accordingly, by moving the first tremor table opposite to the vibration direction with the same distance as the vibration of the slider, and then the vibration of the slider is cancelled (see Japanese Laid Open 8-329476).
Additionally, during the rotation of the turntable, among phenomena that turntable vibrates in its (or the optical disc) radial direction, a technology is provided to avoid the influence on the track pitch due to irregular non-synchronized vibration that is irrelevant to the position of a rotation angle of the turntable. In regard to the exposure apparatus for recording desired information on the optical disc by irradiating laser beams thereon, the exposure apparatus comprises a non-synchronized vibration calculating device for calculating the non-synchronized vibration acted along the radial direction of the turntable, and an adjusting device for adjusting the irradiating positions of the laser beams irradiated on the optical disc according to signals from the non-synchronized vibration calculating device (see Japanese Laid Open 9-190651).
Namely, according to the exposure apparatus mentioned above, in a non-contact way a displacement sensor is placed in the radial direction of the turntable. An origin pulse signal of the turntable is triggered and each rotation position of the turntable is measured previously. And an average value by averaging each vibration amount of the angular position of the rotation is memorized and acuminated. The vibration amount measured during the exposure is subtracted by the average value corresponding to each angular position of the rotation, and then only the amount of the non-synchronized vibration is outputted for correcting the irradiating positions of the laser beams using the adjusting device. In the situation, because the exposure apparatus is able to output the non-synchronized vibration irrelevant to each angular position of the rotation of the turntable, and even though in the exposure process the accuracy of the track pitch is exerted serious problem, the non-synchronized vibration can be immediately detected during the exposure process. The exposure process, therefore, can be terminated. Furthermore, it provides a propagation mechanism that is not affected by the non-synchronized vibration of the turntable.
Therefore, according to the conventional exposure apparatus mentioned above, many improvements are required for exposing the track pitch between adjacent tracks on the optical disc with a high-precision accuracy.
Namely, according to the exposure apparatus disclosed in the Japanese Laid Open 10-293928, the head for irradiating laser beams is fixed on the main body of the exposure apparatus through a tiny sliding device, and the moving stage for installing the turntable used for supporting the optical disc is moved along the direction of the turntable by tiny sliding device fixed on the main body. With respect to the moving position of the moving stage, the position of the head for irradiating laser beams is corrected by the tiny sliding device. Therefore, the track pitches between adjacent tracks are exposed with a high-precision accuracy.
However, because the optical disc is usually placed on the turntable with an eccentricity of several ten xcexcm with respect to the outer radius, the rotation mechanism generates rotational vibration due to the centrifugal force during rotation. Therefore, the irradiation position of the laser beam at side of the turntable varies with the rotation angle, thereby it cannot calculate the correct difference in the propagating direction. As a result, it cannot perform an accurate correction because the tiny sliding device is moved according to the incorrect measured signal. In contrast, track pitches are changed and the exposure quality becomes worse.
In addition, according to the processing method for the optical disc disclosed in the Japanese Laid Open 10-261245, the laser interferometer or the laser holo-scale are assembled for detecting a small propagating deviation of the slider, thereby the small propagating deviation of the slider is optically corrected by deviating the laser beams using an audio optical deviation device. Namely, the laser interferometer or the laser holo-scale is assembled for detecting small propagating deviation of the slider. In addition, the propagating slider and the recording head are integrated by a piezo-actuator. Using the retractable piezo-actuator to let the recording head operate, the tiny propagating deviation of the propagating slider is corrected.
However, because the pitch accuracy formed on the optical disc is determined by the relative vibration between the turntable and the moving stage, it is worse for the correction accuracy to perform the propagating correction by only using the detected result of the slider. As a result, the exposure quality cannot be increased and enhanced.
Next, according to according to disclosure in the Japanese Laid Open 8-329476, in order to eliminate the tiny vibration of the slider according to insufficient propagating servo gain due to that the small vibration of the slider driven by friction and the mechanical resonant frequency of the propagating device are low, a piezoelectric element of the objective lens for fine-tuning positions of a first tremor table is installed on a second tremor table. Accordingly, by moving the first tremor table opposite to the vibration direction with the same distance as the vibration of the slider, and then the vibration of the slider is cancelled.
However, as same as the method in the Japanese Laid Open 10-261245, it is worse for the correction accuracy to perform the propagating correction by only using the detected result of the slider. As a result, the exposure quality cannot be increased and enhanced.
In addition, according to the disclosures in the Japanese Laid Open 10-293928, Japanese Laid Open 10-261245, and Japanese Laid Open 8-329476, because the piezoactuator used as the correction mechanism for the propagating direction is installed on the fore-end or frame of the optical head, the structure is complex and its assembly is very difficult. In addition, the mechanical rigidity is reduced, and the servo gain of the propagating device cannot be set high, which inconvenient control occurs.
Therefore, it is an objective of the invention to provide an exposure apparatus for an optical disc. A laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a base transporting force measuring device is used for measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism. By a controller, according to a result of the base transporting force measuring device, it controls the vibrator to vibrate, thereby the transporting force in the propagating direction acted on the base is cancelled. Therefore, it can suppress the propagating component of the rotational vibration when the optical disc is eccentrically chucked on the rotation mechanism. Thus, the propagation accuracy is increased and the exposure quality is enhanced.
It is another objective of the invention to provide an exposure apparatus for an optical disc. A laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a linear encoder transporting force measuring device is used for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism, wherein the optical linear encoder is used for detecting a propagation of the slider that is used for mounting the condensing device and moveably installed on the base. By a controller, according to a result of the linear encoder transporting force measuring device, it controls the vibrator to vibrate, thereby the transporting force in the propagating direction acted on the linear encoder is cancelled. Therefore, it can suppress the propagating component of the rotational vibration when the optical disc is eccentrically chucked on the rotation mechanism. Thus, the propagation accuracy is increased and the exposure quality is enhanced.
It is another objective of the invention to provide an exposure apparatus for an optical disc. A laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a base transporting force measuring device is used for measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism, and furthermore, a linear encoder transporting force measuring device is used for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism, wherein the optical linear encoder is used for detecting a propagation of the slider that is used for mounting the condensing device and moveably installed on the base. By a controller, according to the results of the base transporting force measuring device and the linear encoder transporting force measuring device it controls the vibrator to vibrate, thereby the transporting forces in the propagating direction acted on the base and the optical linear encoder are cancelled. Therefore, it can suppress the propagating component of the rotational vibration when the optical disc is eccentrically clucked on the rotation mechanism. Besides, the vibrations in the propagating direction due to different propagating paths (relative vibration components having different phases), and the vibrations in the propagating direction from outside can be also suppressed. As a result, the propagation precision is increased and the exposure quality is enhanced.
As mentioned above, the controller performs a feedback control to make the vibrator to vibrate as the result of the base transporting force measuring device, the result of the linear encoder transporting force measuring device, or both the results of the base transporting force measuring device and the linear encoder transporting force measuring device converge to zero. Therefore, the assembly, adjustment and design of the control system for the exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
The vibrator mentioned above can be a voice coil actuator of a coil moving type or a magnetic moving type, and comprises a moving part supported by a supporting spring having a pre-determined resilient constant, and a operation axis fixed to the base at a right angle with respect to a surface of the base, wherein the resilient constant of the supporting spring is set in the vicinity of xcfx89/xcfx89c=21/2 in which xcfx89 is an angular frequency used and xcfx89c is an eigen angular frequency of the vibrator. Therefore, the weight of the vibrator is reduced, and the assembly and adjustment for the exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
In addition, the mass of the moving part of the vibrator and the mass of the optical disc put on the rotation mechanism are set the same. Therefore, the design of the control system for the exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
For achieving the foregoing objectives, the invention provides an exposure apparatus for an optical disc, wherein a laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base, thereby, a pre-determined information is recorded on the optical disc. The exposure apparatus comprises a slider, for mounting the condensing device and moveably installed on the base; a vibrator, installed on the base, and used for vibrating the condensing device along a propagating direction with respect to the base; a base transporting force measuring device, for measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism; and a controller, for controlling the vibrator to vibrate according to a result of the base transporting force measuring device, thereby the transporting force in the propagating direction acted on the base is cancelled.
Therefore, according to the structure of the invention described above, a laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a base transporting force measuring device is used for measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism. By a controller, according to a result of the base transporting force measuring device, it controls the vibrator to vibrate, thereby the transporting force in the propagating direction acted on the base is cancelled. Therefore, it can suppress the propagating component of the rotational vibration when the optical disc is eccentrically chucked on the rotation mechanism. Thus, the propagation accuracy is increased and the exposure quality is enhanced.
For achieving the foregoing objectives, the invention further provides an exposure apparatus for an optical disc, wherein a laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base, thereby, a predetermined information is recorded on the optical disc. The exposure apparatus comprises a slider, for mounting the condensing device and moveably installed on the base; an optical linear encoder, for detecting a propagation of the slider; a vibrator, installed on the base, and used for vibrating the condensing device along a propagating direction with respect to the base; a linear encoder transporting force measuring device, for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism; and a controller, for controlling the vibrator to vibrate according to a result of the linear encoder transporting force measuring device, thereby the transporting force in the propagating direction acted on the optical linear encoder is cancelled.
According to the structure of the invention described above, a laser beam emitted for a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a linear encoder transporting force measuring device is used for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism, wherein the optical linear encoder is used for detecting a propagation of the slider that is used for mounting the condensing device and moveably installed on the base. By a controller, according to a result of the linear encoder transporting force measuring device, it controls the vibrator to vibrate, thereby the transporting force in the propagating direction acted on the linear encoder is cancelled. Therefore, it can supress the propagating component of the rotational vibration when the optical disc is eccentrically chucked on the rotation mechanism. Thus, the propagation accuracy is increased and the exposure quality is enhanced.
For achieving the foregoing objectives, the invention further provides an exposure apparatus for an optical disc, wherein a laser beam emitted for a laser source passes through an exposure system and a condensing device, and then irradiates on the the optical disc put on a rotation mechanism fixed on a base, thereby, a predetermined information is recorded on the optical disc. The exposure apparatus comprised a slider, for mounting the condensing device and moveably installed on the base; a vibrator, installed on the base, and used for vibrating the condensing device along a propagating direction with respect to the base; a base transporting force measuring device, a measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism; a linear encoder transporting force measuring device, for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism; and a controller, for controlling the vibrator to vibrate according to results of the base transporting force measuring device and the linear encoder transporting force measuring device, thereby the transporting forces in the propagating direction acted on the base and the optical linear encoder are cancelled.
According to the structure of the invention described above, a laser beam emitted from a laser source passes through an exposure system and a condensing device, and then irradiates on the optical disc put on a rotation mechanism fixed on a base. When a pre-determined information is recorded on the optical disc, a base transporting force measuring device is used for measuring a transporting force in the propagating direction to the base that is involved a rotation of the rotation mechanism, and furthermore, linear encoder transporting force measuring device is used for measuring a transporting force in the propagating direction to the optical linear encoder that is involved a rotation of the rotation mechanism, wherein the optical linear encoder is used for detecting a propagation of the slider that is used for mounting the condensing device and moveably installed on the base. By a controller, according to the results of the base transporting force measuring device and the linear encoder transporting force measuring device, it controls the vibrator to vibrate, thereby the transporting forces in the propagating direction acted on the base and the optical linear encoder are cancelled. Therefore, it can suppress the propagating component of the rotational vibration when the optical disc is eccentrically chucked on the rotation mechanism. Besides, the vibrations in the propagating direction due to different propagating paths (relative vibration components having different phases), ad the vibrations in the propagating direction from outside can be also suppressed. As a result, the propagation precision is increased and the exposure quality is enhanced.
In the situations above, for example, the controller performs a feedback control to make the vibrator to vibrate as the result of the base transporting force measuring device, the result of the linear encoder transporting force measuring device, or both the results of the base transporting force measuring device and the linear encoder transporting force measuring device converge to zero.
As the structure mentioned above, the controller performs a feedback control to make the vibrator to vibrate as the result of the base transporting force measuring device, the result of the linear encoder transporting force measuring device, or both the result of the base transporting force measuring device and the linear encoder transporting force measuring device converge to zero. Therefore, the assembly, adjustment and design of the control system for the exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
In addition, for example, the vibrator is a voice coil actuator of a coil moving type or a magnetic moving type, and comprises a moving part, supported by a supporting spring having a pre-determined resilient constant, and a operation axis, fixed to the base at a right angle with respect to a surface of the base, wherein the resilient constant of the supporting spring is set in the vicinity of xcfx89/xcfx89c=21/2 in which xcfx89 is an angular frequency used and xcfx89c is an eigen angular frequency of the vibrator.
The vibrator mentioned above can be a voice coil actuator of a coil moving type or a magnetic moving type, and comprises a moving part, supported by a supporting spring having a pre-determined resilient constant, and a operation axis, fixed to the base at a right angle with respect to a surface of the base, wherein the resilient constant of the supporting spring is set in the vicinity of xcfx89/xcfx89c=21/2 in which xcfx89 is an angular frequency used and xcfx89c is an eigen angular frequency of the vibrator. Therefore, the weight of the vibrator is reduced, and the assembly and adjustment for exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
Moreover, the mass of the moving part of the vibrator can be set the same as the mass of the optical disc put on the rotation mechanism.
Accordingly, the mass of the moving part of the vibrator and the mass of the optical disc put on the rotation mechanism are set the same. Threrefore, the design of the control system for the exposure apparatus can be easier. Furthermore, the propagation accuracy is increased and the exposure quality is enhanced with a low cost.
For achieving the foregoing objectives, the invention further provides an exposure apparatus for an optical disc, wherein the optical disc is irradiated by laser beams, thereby a predetermined information is recorded on the optical disc. The exposure apparatus comprises an exposure system; a condensing device for condensing exposure beams directed by the exposure system; a slider fixed on a base for mounting the condensing device and capable of moving along a radial direction of the optical disc; a position detector for detecting the radial position of the slider; a slider controller for controlling the slider according to an output of the position detector, a rotation mechanism opposite to the condensing device and capable of freely rotating, and used for mounting the optic disc, a first display for displaying a propagation deviation signal of the slider; a first measuring device for measuring a vibration amount of the base in a direction perpendicular to the propagating direction; a second display for displaying an output signal of the first measuring device; a second and a third measuring device for measuring rotation amounts of the propagating direction and its perpendicular direction of a rotation part of the rotation mechanism; a first control device for outputting a signal to eliminating a rotational vibration transporting force acted on the base according to frequencies and phases of output signals outputted form the second and the third measuring device; and a first and a second vibrators capable of freely vibrating in the propagating direction and its perpendicular direction according to the signal outputted from the first control device.
For achieving the foregoing objectives, the invention further provides an exposure apparatus for an optical disc, wherein the optical disc is irradiated by laser beams, thereby a predetermined information is recorded on the optical disc. The exposure apparatus comprised an exposure system; a condensing device for condensing exposure beams directed by the exposure system; a slider fixed on a base for mounting the condensing device and capable of moving along a radial direction of the optical disc; a position for detecting the radial position of the slider; a slider controller for controlling the slider according to an output of the position detector; a rotation mechanism opposite to the condensing device and capable of freely rotating, and used for mounting the optic disc; a fourth and a fifth measuring devices, for measuring vibration transporting forces in a propagating direction and its perpendicular direction acted on the base when the rotation mechanism rotates, a first servo control device for outputting a signal to eliminating vibration transporting forces in the propagating direction and its perpendicular direction acted on the base according to output signals outputted from the fourth and the fifth measuring device; a first and a second vibrators capable of freely vibrating in the propagating direction and its perpendicular direction according to the signal outputted from the first servo control device.
As described above, the action points of vibration transporting forces generated by the first and the second vibrators, and an action point of the vibration transporting force in the propagating direction acted on the base when the rotation mechanism rotates are all on a same plane, or the action points are on the same plane and line.
For achieving the foregoing objectives, the invention further provides an exposure apparatus for an optical disc, wherein the optical disc is irradiated by laser beams, thereby a predetermined information is recorded on the optical disc. The exposure apparatus comprises an exposure system; a condensing device for condensing exposure beams directed by the exposure system; a slider fixed on a base for mounting the condensing device and capable of moving along a radial direction of the optical disc; a position detector for detecting the radial position of the slider; a slider controller for controlling the slider according to an output of the position detector; a rotation mechanism opposite to the condensing device and capable of freely rotating, and used for mounting the optic disc; a receiver of an optical linear encoder for detecting a propagation of the slider; a sixth and a seventh measuring devices, for measuring vibration transporting forces in a propagating direction and its perpendicular direction acted on the receiver of the optical linear encoder when the rotation mechanism rotates; a fourth and a fifth measuring devices, for measuring vibration transporting forces in the propagating direction and its perpendicular direction acted on the base when the rotation mechanism rotates, a second servo control device for outputting a signal to eliminating vibration transporting forces in the propagating direction and its perpendicular direction acted on the base and the optical linear encoder according to output signals outputted from the fourth, the fifth, the sixth and the seventh measuring devices; and a first and a second vibrators capable of freely vibrating in the propagating direction and its perpendicular direction according to the signal outputted from the second servo control device, wherein action points of vibration transporting forces generated by the first and the second vibrators, and an action point of the vibration transporting force in the propagating direction acted on the base when the rotation mechanism rotates are all on a same plane, or the action points are on the same plane and line.
In addition, a relative feedback system for converging the output of the measuring devices to zero is formed by the first and the second servo control devices for outputting signals to the first and the second vibrators for eliminating the vibration transporting force in the propagating direction acted on the base when the rotation mechanism rotates.
The first and the second vibrators are fixed on the base and capable of freely vibrating in the propagating direction and its perpendicular direction, and wherein the first and the second vibrators are voice coil actuators of a coil moving type or a magnetic moving type, and comprise a supporting spring having a resilient constant, in which the resilient constant of the supporting spring is set in the vicinity of xcfx89/xcfx89c=21/2 in which xcfx89 is an angular frequency used and xcfx89c is an eigen angular frequency of the vibrator.
The first and second vibrators are capable of freely vibrating in the propagating direction and its perpendicular direction, and wherein the first and the second vibrators are voice coil actuators of a coil moving type or a magnetic moving type, and masses of moving parts of the first and the second vibrators are respectively the same as a mass of the optical disc put on the rotation mechanism are the same.